December Gets Underway

Winter Officially Arrives in December

December has gotten off to a cold and wet start in the Nation’s Capital.  There have already been 0.51” of rain and two colder than average days to start the month.  Fortunately, for those ready for some sunshine, the weather has turned the corner.  Sunshine has returned today and the rest of the week will feature benign, albeit a little cooler than average, weather for the DC Metro Area.  My colleagues and I on the WUSA9 Weather Team will continue to provide the latest weather updates.

“Meteorological winter” officially got underway on December 1 and runs through the end of February.  Average temperatures in the Nation’s Capital will fall throughout the month from a high/low of 52°/37° on December 1 to 44°/29° on December 31.  DC’s warmest December temperature on record of 79° occurred on December 7, 1998.  Conversely, DC’s coldest December temperature of -13° occurred on December 31, 1880.  

It’s interesting to note that while weather records in Washington, D.C. date back to the 1870s, they have been kept at National Airport since 1942.  Given the present day’s urban development, the urban heat island effect is much more pronounced.  For example, DC’s coldest December temperate at National Airport was “only” 4° from December 21, 1942.  More recently, 13 of the last 20 December’s have been warmer than average in Washington, D.C., including seven of the last eight.

 

The Nation’s Capital averages 3.05” of rain and 2.3” of snow in December based on NOAA’s 30-year average from 1981 – 2010.  Snow has occurred in DC during 17 of the last 20 December’s.  Eleven of those 17 December’s have featured measurable snowfall (as opposed to flurries or a “trace” that is too little to measure), with the most recent being in 2017.  

Whether or not December is colder and snowier than average or warmer and drier has little bearing on the rest of the winter.  December 1989, for example, was DC’s coldest since 1917 and had more than four times the monthly snowfall average with 9”.  Meanwhile, the rest of that winter saw a paltry combined snow total of 6.3”.  By comparison, some may remember that December 2015 was DC’s warmest on record and had no measurable snowfall until January during the 2015-2016 winter.  And despite winter not getting underway until relatively late, Washingtonians experienced the fourth largest snowstorm on record from January 22-23, 2016.  

Consequently, once the calendar changes to January, December’s weather events don’t mean much in terms of what the entire winter season will be like.